|
BANDWITH Definitions
Definitions
Asynchronous Transfer Mode (ATM) An international integrated services digital network (ISDN) high-speed, high-volume, packet-switching transmission protocol standard. ATM uses short, uniform, 53-byte cells to divide data into efficient, manageable packets for ultra fast switching through a high-performance communications network. The 53-byte cells contain 5-byte destination address headers and 48 data bytes. ATM is the first packet-switched technology designed from the ground up to support integrated voice, video, and data communications applications. It is well-suited to high-speed wide area network (WAN) transmission bursts.
DS-1,DS1 The equivalent of 24 multiplexed voice grade channels (DS-0s), with a bandwidth of 1.5 Mbps. DS-1 circuits are used to carry moderate volumes of traffic by both end users and carriers.
DS-3,DS3 The equivalent of 28 multiplexed T1 channels, with a bandwidth of 45 Mbps. DS-3 circuits are often used to carry high volumes of long-distance traffic or to provide resold DS-1 or voice-grade private line service. DS-3s are also used by large companies for internal communications.
Optical Carrier (OC-X) Transport levels defined for synchronous optical networks (SONET). The current levels are: - OC-1: 51.84Mbps: 1 DS-3, 28 DS-1, 672 DS-0 - OC-3: 155.52Mbps: 3 DS-3, 84 DS-1, 2016 DS-0 - OC-9: 466.56Mbps: 9 DS-3, 252 DS-1, 6048 DS-0 - OC-12: 622.08Mbps: 12 DS-3, 336 DS-1, 8064 DS-0 - OC-18: 933.12Mbps: 18 DS-3, 504 DS-1, 12096 DS-0 - OC-24: 1244.16Mbps: 24 DS-3, 672 DS-1, 16.128 DS-0 - OC-36: 1866.24Mbps: 36 DS-3, 1008 DS-1, 24,192 DS-0 - OC-48: 2488.32Mbps: 48 DS-3, 1344 DS-1, 32,256 DS-0 - OC-192: 9953.28Mbps: 192 DS-3, 5376 DS-1, 129,024 DS-0
Fractional T-1 A fractional digital service hierarchy level 1 with service in multiples of 56 or 64 Kbps over two channels at 112 or 128 Kbps or above, and up to 23 channels. Common rates for this type of service are 256, 512, 768, and 1024 Kbps. FT-1 uses a portion of a 24-channel T1 circuit. FT1 allows 64 Kbps increments from 2-channel 128 Kbps through all 24 channels at 1.544 Mbps.
Fractional T-3 A fractional digital service hierarchy level 3 with service in multiples of 1.344 Mbps. FT-3 uses a portion of a 672-channel T3 circuit for any mix of voice, data or broadcast-quality video.
Frame Relay A wideband (64 Kbps to 1.544 Mbps) high-speed packet-based data switching interface standard that transmits bursts of data over wide area networks (WANs). Frame-relay packets vary in length from 7 to 1024 bytes. FR is based on link access procedure of D-channels (LAPD) protocol. Since frame relays are data oriented, they are not usually used for voice or video. It has error detection, but has no error correction.
T-1, T1 24 voice channels, each digitized at 64,000 bps, combined into a single 1. 5 Mbps digital stream (8,000 bps signaling), and carried over two pairs of regular copper telephone wires. T1 was used primarily by telephone companies until 1983. Now it is used for dedicated local access to long-distance facilities, long-haul private lines, and for regular local telephone service. Today, most 1.5 Mbps digital streams are called T1, regardless of their makeup or transmission medium. T1 is available in many versions, including: formatted Accunet, a formatted T1 offering that requires compliance with both AT&T DSX-1 hardware and DS1 software standards; and unformatted, which only requires compliance with the DSX-1 standard. The formatted version provides less usable bandwidth.
T-3, T3 A transmission link capable or carrying 44.736Mbps (45 megabits) or 672 voice conversations, more than enough for full-screen, full-motion video. A T3 is the equivalent of 28 multiplexed T1 channels.
Kool Heh...
|
